<?php
//ucwords(string $string, string $separators = " \t\r\n\f\v"): string
// /ucwords — 将字符串中每个单词的首字母转换为大写

$foo = 'hello world!';
$foo = ucwords($foo); // Hello World!
echo $foo;

$bar = 'HELLO WORLD!';
$bar = ucwords($bar); // HELLO WORLD!
$bar = ucwords(strtolower($bar)); // Hello World!
echo "\n";
echo $bar;
